Mitsubishi Heavy Industries KX6 series, Service Manual

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 137 

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 '10 • KX-SM-148

⑥

Drain pipe (continued)

⑤

Refrigerant pipe

⑥

Drain pipe (continued)

2.  Prepare a joint for connecting VP-20 pipe, adhere and connect the joint to the drain hose 

(the end made of rigid PVC), and adhere and connect VP-20 pipe (prepare on site).

※

As for drain pipe, apply VP-20 made of rigid PVC which is on the market.

● 

Make sure that the adhesive will not get into the supplied drain hose.

    It may cause the flexible part broken after the adhesive is dried up and gets rigid.

● 

The flexible drain hose is intended to absorb a small difference at installation of the unit 
or drain pipes. Intentional bending, expanding may cause the flexible hose broken and 
water leakage.

3.  Make sure to make descending slope of greater than 1/100 and do not make up-down bend 

and/or trap in the midway.

●

Pay attention not to give stress on the pipe on the indoor unit side, and support and fix 
the pipe as close place to the unit as possible when connecting the drain pipe.

●

Do not set up air vent.

●

When sharing a drain pipe for more than 
one  unit,  lay  the  main  pipe  100mm 
below  the  drain  outlet  of  the  unit.  In 
addition, select VP-30 or bigger size for 
main drain pipe.

⑧

Panel installation

Drain pump operation 

○

In case electrical wiring work finished

Drain pump can be operated by remote controller (wired).

For the operation method, refer to  Operation for drain pump  in the installation manual for wiring 
work.

○

In case electrical wiring work not finished

     Drain pump will run continuously when the dip switch“SW7-1” on the indoor unit PCB is turned ON, the Connec-

tor CNB is disconnected, and then the power supply (230VAC on the terminal block 

①

 and 

②

) is turned ON.

     Make sure to turn OFF “SW7-1” and reconnect the Connector CNB after the test.

In case of gravity drainage

1.  Remove the rubber plug and insulation from the gravity drainage port.
2.  Connect the drain hose (VP-20) using the Gravity drainage connecting tube (option) and 

secure firmly with a clamp.
(

﹡

If the drain tube is directly connected with the gravity drainage port, the drain pan could not 

be removed.)

3.  Find CNR drain motor connector (blue, 2P) in the control box, and remove it.
  (

﹡

If the unit is used with this connector being connected, the drainage will go out through 

the standard drain connecting port, causing leaks.)

⑦

Wiring-out position and wiring connection

● 

Electrical installation work must be performed according to the installation manual by an 
electrical installation service provider qualified by a power provider of the country, and be 
executed according to the technical standards and other regulations applicable to electrical 
installation in the country. 

      Be sure to use an exclusive circuit.

● 

Use specified cord, fasten the wiring to the terminal securely, and hold the cord securely in 
order not to apply unexpected stress on the terminal.

● 

Do not put both power source line and signal line on the same route. It may cause miscommu-
nication and malfunction.

● 

Be sure to do D type earth work.

● 

For the details of electrical wiring work, see attached instruction manual for electrical wiring 
work.

1.  Remove a lid of the control box (2 screws).
2.  Hold each wiring inside the unit and fasten them to a terminal block securely.
3.  Fix the wiring with supplied screw, nut and washer.
4.  Install the removed parts back to original place. 

750mm or less

100mm or less

295

～

325mm

⑥

Drain pipe

Pipe cover (small)

(For insulation) (Accessory)

Pipe cover (For insulation)

(Prepare on site)

Unit

Pipe cover (big)

(For insulation) (Accessory)

VP-20

(Prepare on site)

Joint for VP-20

(Prepare on site)

VP-20

(Prepare on site)

Drain hose

(Accessory)

Drain socket

 Clamp (Accessory)
(No adhesive allowed)

Gravity drainage port

Control box

Rubber plug

(Remove)

General hard type

PV pipe VP-20

Transparent soft tube

(option)

Connector for drain motor CNR (blue, 2P)

Remove

Insulation

●

Attach the panel on the indoor unit after electrical wiring work.

Work procedure

1.  Using the paper pattern attached as an accessory, check to ensure the unit height and 

ceiling opening are finished true to the specified dimensions.

  Remove the suction panel from the panel assembly. (Ref. below diagram)

2. Among the bolts which are attached to the panel, 2 screw must 

be inserted 5mm at the diagonal positions.

3.  Hang the panel on the 2 bolts and temporarily tighten them.
4.  Tighten the temporarily tightened 2 bolts and the remaining 

2 bolts.

5. Tighten the 2 short bolts (15mm) at the louver supporting section of 

blower outlet central part.

6. Connect the connecter of louver motor and limit switch through the 

side cutout of control box.

7.  When the louver motor does not operate by the remote controller operation, check the 

connection of the connector, turn off the power for 10 seconds or longer, and reset.

Suction panel

Panel assembly

Remove

Short bolt

Louver support

(Sectional view of blower 

 outlet central part)

Pipe diameter

Tightening torque N·m

φ

 6.35

φ

 9.52

φ

 12.7

φ

 15.88

φ

 19.05

14 to 18
34 to 42
49 to 61
68 to 82

100 to 120

Strap (Accessory)

Pipe cover (Accessory)

The thickness of insulation should be 20mm or more.

Earth

Indoor power 

source line

Remote controller 

line

Signal line

(Shielded cord)

CNR

CNJ2

CNM3

CNW1

2

1

X

Y

B

A

Power cable

Earth

Signal cable

 for oller

Passing through this side cutout

Connect to relay connector
in the controll box.

X

Y

B

A

Signal cable

Signal cable for remote controller

Caution

● 

Install the drain pipe according to the installation manual in order to drain properly.

  Imperfection in draining may cause flood indoors and wetting the household goods

，

etc.

● 

Do not put the drain pipe directly into the ditch where toxic gas such as sulfur, the other harmful and

  inflammable gas is generated. Toxic gas would flow into the room and it would cause serious 

damage to user’s health and safety (some poisoning or deficiency of oxygen). In addition, it may 
cause corrosion of heat exchanger and bad smell.

● 

Connect the pipe securely to avoid water leakage from the joint.

● 

Insulate the pipe properly to avoid condensation drop.

● 

Check if the water can flow out properly from both the drain outlet on the indoor unit and the end 
of the drain pipe after installation.

● 

Make sure to make descending slope of greater than 1/100 and do not make up-down bend and/or trap 
in the midway. In addition, do not put air vent on the drain pipe. Check if water is drained out properly 
from the pipe during commissioning. Also, keep sufficient space for inspection and maintenance.

Work procedure
1.  Insert the supplied drain hose (the end made of soft PVC) to the step of the drain socket on 
      the indoor unit and fix it securely with the clamp.

Attach the hose clamp to the drain hose around 10mm from the end.

　  ●

Do not apply adhesives on this end.

Descending slope greater than 1/100

As wide as possible 

(about100mm)

Insulation material

Supporting metal

Descending slope greater than 1/100

Air vent

No bump

No trap

Not touching the water

Trapped air will 

generate noises.

VP-30 or bigger

1.5m~2m

4.  Insulate the drain pipe.

● 

Be sure to insulate the drain socket and rigid PVC pipe installed indoors otherwise it may 

cause dew condensation and water leakage.

※ 

After drainage test implementation, cover the drain socket part with pipe cover (small size), then 

use the pipe cover (big size) to cover the pipe cover (small size), clamps and part of the drain 
hose, and fix and wrap it with tapes to wrap and make joint part gapless.

Drain up

● 

The position for drain pipe outlet can be raised up to 750mm above the ceiling. Use elbows for 
installation to avoid obstacles inside ceiling. If the horizontal drain pipe is too long before vertical pipe, 
the backflow of water will increase when the unit is stopped, and it may cause overflow of water from 
the drain pan on the indoor unit. In order to avoid overflow, keep the horizontal pipe length and offset of 
the pipe within the limit shown in the figure below.

Pipe cover

Pull in the hose pump about 50mm.

Drain test

● 

After installation of drain pipe, make sure that drain system work in good condition and no 

water leakage from joint and drain pan. Check if the motor sound of drain pump is normal 

or not.

● 

Do drain test even if installation of heating season.

● 

For new building cases, make sure to complete the test before hanging the ceiling.

1.  Pour water of about 1000cc into the drain pan in the indoor unit by pump so as not to get 

the electrical component wet.

2.  Make sure that water is drained out properly and there is no water leakage from any joints 

of the drain pipe at the test.

  Confirm that the water is properly drained out while the drain motor is operating. At the 

drain socket (transparent), it is possible to check if the water is drained out properly.

3.  Unplug the drain plug on the indoor unit to remove remaining water on the drain pan after the test, 

and re-plug it. And insulate the drain pipe properly finally.

Pin(B)

Pin(A)

Panel outer

frame

Panel inside 

parts

PJB012D227

A

Caution

●

Use the new refrigerant pipe.

When re-using the existing pipe system for R22 or R407C, pay attention to the following items.

・

Change the flare nuts with the attached ones (JIS category 2), and reprocess the flare parts.

・

Do not use thin-walled pipes.

●

Use phosphorus deoxidized copper alloy seamless pipe (C1220T specified in JIS H3300) for refrigeration pipe installation.

In addition, make sure there is no damage both inside and outside of the pipe, and no harmful 
substances such as sulfur, oxide, dust or a contaminant stuck on the pipes.

●

Do not use any refrigerant other than R410A.

Using other refrigerant except R410A (R22 etc.) may degrade inside refrigeration oil. And air getting into 

refrigeration circuit may cause over-pressure and resultant it may result in bursting, etc.

●

Store the copper pipes indoors and seal the both end of them until they are brazed in order to avoid any dust, dirt or 
water getting into pipe. Otherwise it will cause degradation of refrigeration oil and compressor breakdown, etc.

●

Use special tools for R410 refrigerant.

Work procedure 

1.  Remove the flare nut and blind flanges on the pipe of the indoor unit.

※ 

Make sure to loosen the flare nut with holding the nut on pipe side with a spanner and giving 

torque to the nut with another spanner in order to avoid unexpected stress to the copper 
pipe, and then remove them.

(Gas may come out at this time, but it is not abnormal.)

● 

Pay attention whether the flare nut pops out. (as the indoor unit is sometimes pressured.)

2.  Make a flare on liquid pipe and gas pipe, and connect the refrigeration pipes on the indoor unit.

※

Bend  the  pipe  with  as  big  radius  as  possible  and  do  not  bend  the  pipe  repeatedly.  In 

addition, do not twist and crush the pipes.

※

Do a flare connection as follows:

● 

Make sure to loosen the flare nut with holding the nut on pipe side with a spanner and giving 

torque to the nut with another spanner in order to avoid unexpected stress to the copper 
pipe, and then remove them.

● 

When fastening the flare nut, align the refrigeration pipe with the center of flare nut, screw 

the  nut  for  3-4  times  by  hand  and  then  tighten  it  by  spanner  with  the  specified  torque 
mentioned in the table below. Make sure to hold the pipe on the indoor unit securely by a 
spanner when tightening the nut in order to avoid unexpected stress on the copper pipe.

3.  Cover the flare connection part of the indoor unit with attached insulation material after a gas 

leakage inspection, and tighten both ends with attached straps.

●

Make sure to insulate both gas pipes and liquid pipes completely.

※ 

Incomplete insulation may cause dew condensation or water dropping. 

4.  Refrigerant is charged in the outdoor unit.
  As for the additional refrigerant charge for the indoor unit and piping, refer to the installation 

manual attached to the outdoor unit.

⑨

Check list after installation

●

Check the following items after all installation work completed.

Check if

Expected trouble

Check

The indoor and outdoor units are fixed securely?

Falling, vibration, noise

Inspection for leakage is done?

Insufficient capacity

Insulation work is properly done?

Water leakage

Water is drained properly?

Water leakage

Supply voltage is same as mentioned in the model name plate?

PCB burnt out, not working at all

There is mis-wiring or mis-connection of piping?

PCB burnt out, not working at all

Earth wiring is connected properly?

Electric shock

Cable size comply with specified size?

PCB burnt out, not working at all

Any obstacle blocks airflow on air inlet and outlet?

Insufficient capacity

Fasten the screw within

5 mm left to the nut

Hose clamp

Drain hose

Drain socket

Metal plate

10mm